Liquid sample analyzers for analyzing liquid samples such as blood and urine are widely known. Such liquid sample analyzers have a sample aspirating part (pipette) for aspirating a liquid sample in a container, and analyze the aspirated liquid sample via an analyzing part. Furthermore, such liquid sample analyzers have a function of monitoring whether or not a sample is aspirated normally.
Japanese Laid-Open Patent Publication No. 59-65769 discloses this type of sample aspirating apparatus. The sample aspirating apparatus disclosed in Japanese Laid-Open Patent Publication No. 59-65769 is provided with a first liquid sensor and a second liquid sensor, respectively, on bilateral sides of a sampling valve for measuring the sample aspirated by a sample aspirating pipette, so as to monitor whether or not a sample has been aspirated normally by whether or not the first liquid sensor and second liquid sensor detect a sample.
Moreover, Japanese Laid-Open Patent Publication No. 62-163968 discloses a pipette for confirming a liquid amount wherein a light transmitting part and a light blocking part are alternatingly arranged at predetermined spacing along the lengthwise direction of the pipette. This pipette for confirming a liquid amount is formed of transparent material such as quartz glass, hard transparent glass or the like. The surface has aluminum foil or the like vacuum deposited at predetermined spacing along the lengthwise direction. When light is emitted from a light emitting element, the light crosses through the pipette so as to be transmitted therethrough. The amount of liquid is verified by the light receiving element receiving the light from the light emitting element.
The sample aspirating apparatus disclosed in the Japanese Laid-Open Patent Publication No. 59-65769 requires measuring a sample via a sampling valve, however. Although the sampling valve is suited for simultaneously measuring and dividing a sample into a plurality of aliquots, such a valve is expensive and a large amount of sample is not used for analysis (dead volume) due to the need for a flow path from the pipette to the sampling valve.
Furthermore, the pipette for confirming a liquid amount disclosed in the Japanese Laid-Open Patent Publication No. 62-163968 requires high precision in the processing of the pipette used to measure minute samples, and such precision processing is problematic inasmuch as the pipette is formed of glass material such as quartz glass, hard transparent glass or the like.